Sprinter Patrick Johnson has become the first Australian to break the magic 10-second barrier for 100m, clocking 9.93sec in Mito, Japan.

Johnson won the 100m final with a legal tailwind of 1.8 metres per second to become the fastest Australian in history, shattering Matt Shirvington's national record of 10.03 set in 1998.

It was a case of third time lucky for Canberra-based, Queensland-born Johnson, who twice broke the 10-second barrier in Perth in February.

But his 9.88 and 9.90 times were set with an illegal tailwind and didn't count as official records.

Johnson, 30, becomes the fastest man in the world this year, the 17th fastest man of all time and only the 39th man to clock a legal sub 10-second time.

"It was more a relief than anything and I'm glad to have put Australia on the map in terms of sprinting," Johnson told AAP from Japan tonight.

"I've been knocking on the door but conditions haven't helped me.

"It's nice to get this out of the way so now I can move on to the next level.

"Now I have to be consistent. There's no point just doing it once."

Johnson signalled his intentions early, clocking a personal best 10.05sec in the morning heats before powering to victory in the final at Mito, 100km north of Tokyo.

Brought to you by AAP © 2024 AAP